Method of fabricating grabbing face of sample grabbing portion
By working a grabbing portion by a charged particle beam of FIB or the like, the grabbing portion in parallel with the beam can be formed, and also dust adhered to the grabbing portion is removed. When a small sample represented by a TEM sample is fabricated by being cut out by etching by a charged particle beam and is carried at inside of an apparatus of irradiating a charged particle beam, the sample is etched in a direction of irradiating the charged particle beam, and therefore, a mechanism pinched by a grabbing face of a grabbing portion can be worked in a direction the same as that in working the sample, and therefore, a change in an attitude can be reduced when the sample and the grabbing face are fabricated by parallel faces.
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This application claims priority under 35 U.S.C.§119 to Japanese Patent Application No. JP2006-344412 filed Dec. 21, 2006, the entire content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTIONThe present invention relates to an analyzing apparatus such as a focused ion beam (FIB) apparatus, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a scanning probe microscope (SPM), and relates to a tool for handling, or separating, picking up, storing a small sample or the like and having a function of working a small sample used for TEM observation or grabbing and carrying a small sample in observation.
While observing a small sample by SEM or an FIB microscope (SIM), a portion of a conductor wafer or the like is cut out and picked up to be transferred to a sample base or the like to be fixed in cutting out a failed defect portion for working a TEM sample. There is means for transferring such a small picked-up sample constituted by using a single or a plurality of bimorph type piezoelectric elements, or finely moved by a stepping motor. At a front end of a driving portion, there is present a slender needle-like constitution referred to as prove, or a grabbing tool comprising a plurality of pieces of support members or the like. In the case of the probe, a sample is fixed by forming a deposition film between the front end of the probe and the sample by irradiating a charged particle beam while supplying a gas, a sample is attracted by static electricity of the front end to be transferred, and therefore, it is difficult to control a position of the sample in transferring the sample. Further, in the case of a grabbing member, when the sample is grabbed, it is a factor of determining a sample carrying success rate whether a shape thereof is easy to be grabbed, or an operability thereof is excellent.
JP-A-2003-217494 (page 2, FIG. 1) proposes a charged particle beam apparatus including a laminated type piezoelectric element block for handling a small part. Two sheets of plates having sharp front ends are constituted by bimorph type piezoelectric elements, and function as an opening/closing grabbing member by making the two sheets proximate to each other or remote from each other by applying a voltage. A small part constituting an object of observation is carried to an aimed location and thereafter connected to a power source line by a W deposited film by a focused ion beam in a gas atmosphere of W (CO)6.
Japanese Patent Publication No. 3109220 proposes a gripper in which a grabbing member is constituted by a flexible finger having a function of grabbing by deforming the flexible finger by a Lorenz force.
Further, JP-A-8-257926 (page 4, FIG. 1) proposes an integrating method in which when the flexible finger of Japanese Patent Publication No. 3109220 is integrated, positions of front ends of grabbing portions are matched. According to the integrating method, grabbing front end members are connected to a cabinet by electrodes, thereafter, the two grabbing members are bonded by adjusting a position of the cabinet such that positions of the grabbing members are opposed to each other.
However, when a mechanism of grabbing and carrying a small sample as described in the background art of the preceding item is used, it is conceivable to bring about a change in an attitude and a shift in an angle of a small sample owing to a shape of the front end of the grabbing member. Therefore, the sample cannot be grabbed by a desired attitude by the grabbing mechanism, and therefore, it is difficult to transfer the grabbed sample in a desired attitude. Further, when the attitude of the sample is shifted, it is necessary to adjust the angle by operating a mechanism of grabbing the sample by a stage. Further, when the attitude is shifted to outside of a movable range of the stage, the attitude cannot be corrected. In order to resolve the above-described problem, shapes of the grabbing portion and the sample need to be aligned accurately within a correcting range. The invention provides a method of resolving the above-described problem and accurately grabbing and transferring a small sample.
SUMMARY OF THE INVENTIONThere is proposed a method of preventing an attitude of a small sample from being changed considerably when the small sample is grabbed by a grabbing member by fabricating a grabbing face of a sample grabbing portion of a sample carrying mechanism along a beam irradiating axis by a charged particle beam. A method of adjusting a grabbing face of the invention is a working method paying attention to the fact that three of a direction of working a sample relative to a direction of irradiating a charged particle beam when a front end portion of a sample grabbing portion is worked by etching by a charged particle beam of FIB or the like, a direction of working a front end of a grabbing portion, and a direction of observing an image when the charged particle beam is scanned are the same. When a small sample represented by a TEM sample is cut out by etching to be carried at inside of a charged particle beam apparatus, the small sample is etched in a direction of irradiating the charged particle beam, and therefore, a face squeezed by the grabbing portion can be worked by the direction the same as that of working the sample. By fabricating the sample and the grabbing portion by parallel faces in working by etching, a change in an attitude when the sample is grabbed can be reduced.
In consideration of the fact of providing a method of constituting a shape suitable for carrying a small sample with regard to a grabbing shape, that is, the fact that when the small sample is carried, the sample is influenced by the shape of the sample, recesses and projections or an angular attitude of a mechanism of grabbing the sample, by working the grabbing portion by the charged particle beam of FIB or the like, the grabbing portion in parallel with the beam can be formed, further, also dust adhered to the grabbing portion is removed. By the above-described foreign object removing effect, a pertinent angle when the sample is grabbed can be provided.
According to the method of the invention, an image can be provided by scanning the charged particle beam in working, the charged particle beam is functioned as SEM in a case of an electron and functioned as FIB in a case of ion, and an accuracy of working the grabbing face can be confirmed as an image in view from the beam irradiating direction.
Further, from reason that when the sample is worked by etching, a shape profile of the beam is constituted by a normal distribution, an ideal working shape is not provided, and therefore, there is present a method of working a strict angle by irradiating a beam normally from an angle skewed more or less by 1° from an upper face of the sample by a sputter process of FIB or the like. When the grabbing portion is provided with an angle adjusting mechanism capable of dealing with vertical working, the strict angle adjustment of the grabbing face may be carried out.
A TEM sample is realized to be moved and installed safely and swiftly by grabbing a small sample by pertinent angle by the above-described method without destructing or losing the sample by a failure.
A grabbing and carrying mechanism used in realizing a method of grabbing a small sample by etching by a beam of the invention includes an actuator having front end members comprising 2 pieces of needle-like members for grabbing the sample, arranging the 2 pieces of needle-like members to be opposed to each other by making the needle-like members always proximate to each other or providing a predetermined gap therebetween and driving the 2 pieces of the needle-like members.
According to the method of grabbing a small sample of the invention, the grabbing face is formed in the beam irradiating direction by working by the charged particle beam, and therefore, grabbing the sample for the small sample can be carried out by an accuracy exceeding an accuracy of fabricating the sample grabbing portion. Further, the grabbing face can be confirmed to be formed by an image provided by scanning the charged particle beam. Further, as a result thereof, the grabbing force can be promoted by forming the grabbed face of the sample for fabricating the sample grabbing face and the grabbing face of the grabbing portion characterized in removing dust or recesses or projections of the grabbing portion by irradiating the beam in the same direction.
When the method of grabbing the small sample of the invention is used, a rotational axis necessary for rectifying the attitude when the sample is grabbed to be lifted becomes unnecessary and a mechanism of controlling an attitude of the sample grabbing portion can be omitted.
Further, when a planer shape substantially in parallel with the direction of irradiating the charged particle beam is formed, by reason that the charged particle beam is distributed by a beam current density or an etching component is adhered again, an accurate plane completely in parallel with a direction of irradiating the charged particle beam cannot be formed, and therefore, when the grabbing face is formed, by setting an angle of irradiating the charged particle beam in a direction of being skewed from the aimed direction of the grabbing face by several degrees, the inherently aimed grabbing face can be formed further accurately.
According to a method of grabbing a small sample of the invention, for resolving the problem of the attitude control, there is proposed a method of making contact faces of a small sample and a grabbing face parallel in a state in which an irradiated charged particle beam is irradiated to a small sample and a grabbing portion in the same direction. A small sample and a sample grabbing and carrying mechanism are installed at inside of the same vacuum chamber for using the charged particle beam, and for monitoring the attitude control, a secondary electron image or a reflected electron image or the like provided by scanning the charged particle beam is utilized.
According to a small sample grabbing method of the invention, a stable grabbing method with an object of carrying a small sample 20 is shown, and when the small sample 20 used for TEM observation or the like is not previously fabricated, an arbitrary observation portion is cut out from a circuit board or the like and is carried.
An attitude of the sample pulled up in
Further, a mode of a method of driving the grabbing portion 18 is not limited such that the grabbing portion 18 may be operated by a piezoelectric, electromagnetically driven, or electrostatic actuator or such as a device of an MEMS mechanism fabricated by a semiconductor process.
EXAMPLE 1Although an explanation has been given of the method of grabbing the sample worked by the charged particle beam, even when an object which is not needed to be worked by the charged particle beam, a sample piece worked by other apparatus or the like is charged by tweezers, a method of working grabbing faces of the tweezers by the charged particle beam such that the grabbing faces are in parallel with grabbed faces of a sample by the above-described method is effective.
Further, although a description has been given of the method of fabricating the grabbing face of the sample grabbing portion in the above-described examples, also a sample carrying mechanism having a sample grabbing portion having a grabbing face fabricated by the above-described method falls in the range of the invention.
Claims
1. A method for carrying a sample comprising the steps of:
- etching a grabbing portion of a grabbing member using a charged particle beam
- in order to form grabbing faces of the grabbing portion that are substantially in parallel with a grabbed face of the sample; and
- carrying the sample by grabbing the sample with the etched grabbing portion.
2. The method for carrying a sample according to claim 1, wherein the charged particle beam is a focused ion beam.
3. The method for carrying a sample according to claim 1, further comprising:
- etching a periphery area of the sample with the charged particle beam while supplying a gas for promoting the etching.
4. The method for carrying a sample according to claim 1, wherein etching the grabbing portion further comprises etching the grabbing portion of the grabbing member using an electron beam while supplying a gas suitable for promoting the etching.
5. The method for carrying a sample according to claim 1, wherein forming the grabbing faces of the grabbing portion further comprises:
- setting an angle of irradiating the charged particle beam to be in a direction of being skewed to the grabbing face of the grabbing portion by several degrees.
6. The method for carrying a sample according to claim 1, further comprising:
- adjusting an angle of a sample stage or the grabbing member such that an angle of incidence of the charged particle beam when the grabbed face of the sample is formed and an angle of incidence when the grabbing face is formed are identical.
7. The method for carrying a sample according to claim 1, further comprising:
- etching the grabbed faces of the sample to be vertical; and
- scanning the grabbing face of the grabbing member with the charged particle beam in the same direction as the vertical direction of the grabbed faces.
8. The method for carrying a sample according to claim 7, the sample is a sample for observing by a transmission Electron Microscope (TEM).
9. The method for carrying a sample according to claim 7, wherein the sample is a sample for producing an atom probe of an atom probe electric field microscope.
10. The method for carrying a sample according to claim 1, wherein the sample is an optical device.
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Type: Grant
Filed: Dec 19, 2007
Date of Patent: May 31, 2011
Patent Publication Number: 20080156770
Assignee: Sii Nanotechnology Inc. (Chiba)
Inventor: Masanao Munekane (Chiba)
Primary Examiner: Shamim Ahmed
Attorney: Brinks Hofer Gilson & Lione
Application Number: 11/960,304
International Classification: C23F 1/00 (20060101);